Iteration expansion and regional evolution: phylogeography of Dendrobium officinale and four related taxa in southern China

Abstract

The genus Dendrobium was used as a case study to elucidate the evolutionary history of Orchidaceae in the Sino-Japanese Floristic Region (SJFR) and Southeast Asia region. These evolutionary histories remain largely unknown, including the temporal and spatial distribution of the evolutionary events. The present study used nuclear and plastid DNA to determine the phylogeography of Dendrobium officinale and four closely related taxa. Plastid DNA haplotype and nuclear data were shown to be discordant, suggesting reticulate evolution drove the species’ diversification. Rapid radiation and genetic drift appeared to drive the evolution of D. tosaense and D. flexicaule, whereas introgression or hybridization might have been involved in the evolution of D. scoriarum and D. shixingense. The phylogeographical structure of D. officinale revealed that core natural distribution regions might have served as its glacial refuges. In recent years, human disturbances caused its artificial migration and population extinction. The five taxa may have originated from the Nanling Mountains and the Yungui Plateau and then migrated northward or eastward. After the initial iteration expansion, D. officinale populations appeared to experience the regional evolutionary patterns in different regions and follow the sequential or rapid decline in gene exchange.

Accurate authentication of Dendrobium officinale and its closely related species by comparative analysis of complete plastomes

“…However, the mutational hotspots for the intraspecific-level studies of Dendrobium species were still uncertain. For example, the loci of trnC - petN and trnE - trnT were employed to investigate the phylogeographic relationship among different population of D. moniliforme 53 , while the loci of accD - psaI , trnC - petN , and rps15 - ycf1 were used to infer the phylogeographic history of D. officinale 15 . Thus, aiming to identify the mutational hotspots or combinations applicable for the intraspecific-level studies of Dendrobium species, we estimated the pairwised intraspecific SV of 90 syntenic non-coding loci of D. officinale and its closely related species.…”

“…However, Dendrobium species have been documented to be difficult for discrimination analysis due to their similar appearance and tissue structure 9 , 10 , 11 . Among them, D. officinale and its closely related species are a particularly difficult group for identification studies and phylogenetic analyses due to the overlapping morphological variations 14 , 54 , 55 , complex evolutionary histories 15 , and the lack of effective molecular markers. Previous molecular identification and phylogenetic studies about this group were generally focused on one or a few DNA regions, but none of them successfully resolved relationships among the 6 species, which was mainly due to the inadequate variations provided by a limited number of DNA loci 14 , 19 , 20 , 21 , 22 , 23 .…”

“…Unfortunately, these methods are unable to distinguish D. officinale from several Dendrobium species, especially 5 closely related species of it ( D. tosaense Makino; D. shixingense Z. L. Chen, S. J. Zeng et J. Duan; D. flexicaule Z. H. Tsi, S. C. Sun et L. G. Xu; D. scoriarum W. W. Smith; D. aduncum Lindl.) 14 , 15 because of their close affinities.…”

The Effects of Ecological Factors on the Main Medicinal Components of Dendrobium officinale under Different Cultivation Modes

“…Dendrobium is a perennial medicinal plant belonging to Orchids family in plant taxonomy, and it is one the largest genera in Orchidaceae, comprising approximately 1500-2000 species distributed in the tropical and subtropical regions of Asia and North Australia [1,2]. In China, there are 74 species and two varieties of Dendrobium [3], mainly distributed in Anhui, Zhejiang, Fujian and other places in China, which contain polysaccharides, alkaloids, flavonoids, essential amino acids and some trace mineral elements [4,5].…”

In vitro seed germination and seedling growth of the orchid Dendrobium primulinum Lindl.

“…In South-east Asia, especially in the lap of the Himalayas of Nepal, a total of 90 species of orchids have been recognized to have medicinal values (Pant and Rascoti, 2013). Hara et al (1978) (Hou et al, 2017). Dendrobium primulinum is one of the important Dendrobium species, which is commonly called Primrose yellow Dendrobium Callista primulina, or Dendrobium nobile var pallidiflorum; it is a beautiful species of the genus Dendrobium.…”